Ace the Wyoming Pesticide Applicator Exam 2024 – Conquer the Green Frontier!

Vapor pressure is the property that causes a chemical to evaporate. This is because vapor pressure is a measure of the tendency of a substance to escape or vaporize from a liquid or solid state into the surrounding atmosphere. As for the other options, boiling point does not necessarily cause a chemical to evaporate as some chemicals can evaporate at room temperature. Density is a measure of the mass per volume and does not directly affect the ability of a substance to evaporate. Viscosity is the resistance of a fluid to flow and does not play a significant role in evaporation. Therefore, the best answer is option D, vapor pressure.